IEICE Information and Communication Technology Forum
Extended Sub-sampling in OFDM Environment
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The sub-sampling method for Orthogonal Frequency Division Multiplexing (OFDM) that has been recently proposed by the author, is extended in this paper allowing the Analog-to-Digital Converter (ADC) of the receiver to operate in low power mode, up to ¾ of the time. The predictability of the parity patterns generated by the Forward Error Correction encoder (FEC) of the transmitter when it accepts as imput sparse data is exploited in order to define appropriate Inverse Fast Fourier Transform (I-FFT) input symbol arrangements. These symbol structures allow the substitution of a number samples by others that are already available on the receiver side. Moreover, several FFT and IFFT operations can be deactivated because they output zeros when they accept as input a number of identical values. The advantages of the proposed method are: low power, higher speed, fewer memory resources and most importantly implementation with very low cost hardware. The simulation results show that full input signal recovery or at least a very low Bit Error Rate (BER) in the order of 10-4 is possible in most of the cases that have been tested.